From patchwork Fri Mar 14 06:15:03 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shakeel Butt X-Patchwork-Id: 14016303 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id DED53C28B2F for ; Fri, 14 Mar 2025 06:15:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 94D6E280005; Fri, 14 Mar 2025 02:15:34 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8FF5F280003; Fri, 14 Mar 2025 02:15:34 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7EFE3280005; Fri, 14 Mar 2025 02:15:34 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 59A00280003 for ; Fri, 14 Mar 2025 02:15:34 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 25EA6B77DD for ; Fri, 14 Mar 2025 06:15:35 +0000 (UTC) X-FDA: 83219145030.18.0058FA9 Received: from out-174.mta0.migadu.com (out-174.mta0.migadu.com [91.218.175.174]) by imf09.hostedemail.com (Postfix) with ESMTP id 6DB7414000C for ; Fri, 14 Mar 2025 06:15:33 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=FeQvgZ0y; spf=pass (imf09.hostedemail.com: domain of shakeel.butt@linux.dev designates 91.218.175.174 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1741932933; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=4gcQPtwIR/hVm1yRr4cRacE1bGrzLqevTybXQMDqJ14=; b=0DO9ZBCAe+sxunLxV/Fget9gqUmN8jnqRJysSuk9wU2P43b8eOzrdr509Fgbn1YF3G5nAQ vIBXsUffwV0n8t3k1QqaNgZgbrGvoQK8Bc56OJoMBle3xO2SWNE9YO9lloVMhQEeLLnfLf iiaFHE5QaSupUV+/MtG1v1qdaF0t6D4= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1741932933; a=rsa-sha256; cv=none; b=ijO3sAIAozuzaCslxobAw8cKC4Y0docAdXttHohqnau0Z5tPqsUDBwRjtz/E0/+fMIIWGq xkP9tGfL4uAgtHSCiJk/TuuuntHQccQwE5PzA5PhsNbS/GkzkOUPZL5xnajeVZnB0LczZH ChmCok5YlMlPomDpGCjEv/y5dOZaamI= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=FeQvgZ0y; spf=pass (imf09.hostedemail.com: domain of shakeel.butt@linux.dev designates 91.218.175.174 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1741932932; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4gcQPtwIR/hVm1yRr4cRacE1bGrzLqevTybXQMDqJ14=; b=FeQvgZ0yXEZ1YmVQs936nWoNHKfUiPJcFKFvpqK16/CwDxmnMaVmA7QENZTzMSIQbHs7WV BdIx05IJWLFoRUTmqjG0ITtgCcDG/oQDslGjV7+zAa+Ar1pyCIytzoVik0svc/mmlR+U1G xzLDhIBey5JN/Ok/Tv5oW3YZhsF2aIA= From: Shakeel Butt To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Vlastimil Babka , Sebastian Andrzej Siewior , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Meta kernel team Subject: [RFC PATCH 02/10] memcg: decouple drain_obj_stock from local stock Date: Thu, 13 Mar 2025 23:15:03 -0700 Message-ID: <20250314061511.1308152-3-shakeel.butt@linux.dev> In-Reply-To: <20250314061511.1308152-1-shakeel.butt@linux.dev> References: <20250314061511.1308152-1-shakeel.butt@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 6DB7414000C X-Stat-Signature: jy6c8zj36pnnxht6g13di4t3wwop19r3 X-HE-Tag: 1741932933-77869 X-HE-Meta: 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 vc3aff5m HN+OsWd8My6nPz2OTgiIK2l8QDO2qGqnHjBOMdXzhitQI17N5SweBCTtL5cGV1x9lkVjWTgEku985izdo3x6kpXMTjzvp9qsp66obVutw/lawCZqpYjXrNH10yTpvZpV+6/iOfBWMD39RY2OZjH0CjDuOdWZrSOmMU6w/0zykmrJ6xP8xejvBLEOkVIvfomYyIopgFzQjyXYVZwIzmtbqBGZ6Sw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000012, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Currently drain_obj_stock() can potentially call __refill_stock which accesses local cpu stock and thus requires memcg stock's local_lock. However if we look at the code paths leading to drain_obj_stock(), there is never a good reason to refill the memcg stock at all from it. At the moment, drain_obj_stock can be called from reclaim, hotplug cpu teardown, mod_objcg_state() and refill_obj_stock(). For reclaim and hotplug there is no need to refill. For the other two paths, most probably the newly switched objcg would be used in near future and thus no need to refill stock with the older objcg. In addition, __refill_stock() from drain_obj_stock() happens on rare cases, so performance is not really an issue. Let's just uncharge directly instead of refill which will also decouple drain_obj_stock from local cpu stock and local_lock requirements. Signed-off-by: Shakeel Butt Acked-by: Vlastimil Babka --- mm/memcontrol.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c09a32e93d39..28cb75b5bc66 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2855,7 +2855,12 @@ static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock) mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages); memcg1_account_kmem(memcg, -nr_pages); - __refill_stock(memcg, nr_pages); + if (!mem_cgroup_is_root(memcg)) { + page_counter_uncharge(&memcg->memory, nr_pages); + if (do_memsw_account()) + page_counter_uncharge(&memcg->memsw, + nr_pages); + } css_put(&memcg->css); }